Abstract : As-received wafers of n- and p-type 6H-SiC(0001) were etched via gaseous HCl in H2 at 1350 deg C at NASA-Lewis to remove cutting and polishing scratches from the surface; however, etch pits were created. GaN films have been deposited on Si(100) and Al2O3(0001) substrates using triethylgallium and NH3 seeded into highly expanded He gas streams. A two-step deposition process that repeatedly resulted in continuous crystalline GaN films has been developed. The microstructure and composition of the resultant films were characterized by SEM, RHEED and AES and film character correlated to deposition conditions. Assembly of a new dual seeded beam deposition and film analysis facility is underway. In addition, the main chamber of a dual Colutron ion-beam deposition system for the deposition of high-quality SiC and GaN films is nearing completion. Ion sources have been assembled and leak-tested. Preliminary results on the characterization of a seeded supersonic molecular beam source are presented. A room temperature beam of 10% NH3 with a source pressure of 25 kTorr and a 25 micrometers nozzle produces NH3 molecules with mean energies of 0.264 eV and an energy spread of 0.068 eV. Modifications to the existing system are discussed.